Trajectory of gestational weight gain is related to birthweight: The TAWS cohort study in China.

Few studies have reported the timing and amount of gestational weight gain (GWG) to prevent large-for-gestational-age (LGA) or small-for-gestational-age (SGA). This study aimed to evaluate the association of GWG velocity in each trimester with LGA or SGA based on data from the Taicang and Wuqiang cohort study (TAWS, n = 2008). We used a linear mixed model to evaluate the association of trimester-specific GWG velocity with birthweight categories and stratified by prepregnancy body mass index category and parity. For normal-weight pregnant women, mothers with LGA births had higher GWG velocities than mothers with appropriate-for-gestational-age (AGA) births in the first trimester (0.108 vs. 0.031 kg/week, p < 0.01), second trimester (0.755 vs. 0.631 kg/week, p < 0.01) and third trimester (0.664 vs. 0.594 kg/week, p < 0.01); in contrast, mothers with SGA births had lower GWG velocities than mothers with AGA births in the second trimester (0.528 vs. 0.631 kg/week, p < 0.01) and third trimester (0.541 vs. 0.594 kg/week, p < 0.01). For normal-weight pregnant women with AGA births, multiparous women had lower GWG velocities than primiparous women in the second (0.602 vs. 0.643 kg/week, p < 0.01) and third trimesters (0.553 vs. 0.606 kg/week, p < 0.01). Therefore, for normal-weight women, LGA prevention would begin in early pregnancy and continue until delivery and the second and third trimesters may be critical periods for preventing SGA; in addition, among normal-weight pregnant women with AGA births, multiparous women tend to have lower weight gain velocities than primiparous women.